I went from the LS7 Clutch and 7/8" bore when I had my LS1 engine. It sounds very similar to the specs on your current clutch. I didn't like that it was so stiff, but I lived with it. Then when I was building my LS3 with LSA supercharger, I needed something that would hold around 800 flywheel HP. I picked up an RXT clutch from McLeod, and I loved it. I also swapped out to a 3/4" bore MC and with that combo, it was just slightly more stiff than what you'd expect from a stock clutch, but would grab like no tomorrow. I would highly recommend that clutch, and possibly going with a hydraulic setup. I would probably go with the RST clutch since the RXT is rated for 1200 HP.